Enhanced photoluminescence of ZnO∕Er2O3 core-shell structure nanorods synthesized by pulsed laser deposition

A narrow size distribution of ZnO nanorod array has been synthesized on silicon substrate by pulsed laser deposition (PLD) in argon ambient. ZnO∕Er2O3 core-shell nanostructures were then formed through PLD of a thin Er2O3 layer onto the fabricated ZnO nanorod surface. Transmission electron microscopy analysis shows that both the ZnO core and Er2O3 shell are polycrystalline. Photoluminescence measurement was carried out to characterize the optical properties of the core-shell nanostructures. The band diagram of the core-shell structure shows that a type-II nanostructure may have formed, which explains the ultraviolet emission enhancement of the core-shell structure over pure ZnO nanorods.